Due to their excellent electrical and mechanical properties, single-walled carbon nanotubes have been widely applied in logic circuits and optical electronic devices, including field-effect transistors, inverters, ring oscillators and light emitting devices etc.
Synthesis of single-walled carbon nanotubes is mainly through chemical vapor deposition, arc discharge, or laser ablation, etc. The single-walled carbon nanotubes synthesized by these above approaches contain ˜⅔ of semiconducting carbon nanotubes and ˜⅓ of metallic carbon nanotubes.
Purification of semiconducting carbon nanotubes mainly includes a gel method, density gradient centrifugation, and polymer sorting, etc. Although high-purity single-walled semiconducting carbon nanotubes can be obtained by these above approaches, large-scale production has always been a challenge. Currently, the emergence of disordered carbon nanotube films has brought hope to this challenge. To date, carbon nanotube films with uniform distribution have been able to be prepared in large scale.
Utilization in field-effect transistors shall be an important application of carbon nanotube films. During fabrication of field-effect transistors, the bipolarity of carbon nanotubes that arises due to exposure to oxygen in the air may adversely affect the stability, reliability and mobility rate of the field-effect transistors. A reliable packaging method, therefore, is highly needed for the manufacturing of transistors with favorable features including high reliability, stability, and mobility rate.